NNR #3

Hi Kabren,

So I got to listen to two of your podcasts this week. Cool. I really like the Podsafe music.

I wanted to explain about Intel Macs and how they will run your PowerPC applications. There’s a dynamic translator built-in to the Intel version of Mac OS X called “Rosetta”. If you’re on an Intel Mac and you run a PowerPC application, the Mac OS will recognize that this is a PPC executable and will launch “Rosetta” which will dynamically translate your PPC (G4/G5) code into Intel (X86) code. Once this is translated in Intel code, it will then run, however it will not run as fast since it is not “native” to that machine.

If you want the official technical scoop on Rosetta, see Apple’s web site:

http://developer.apple.com/documentation/MacOSX/Conceptual/universal_binary/universal_binary_exec_a/chapter_7_section_1.html

Back when Apple transitioned from Motorola 68K to PowerPC, they used to do something similar. If you were on a PowerPC computer and you executed 68K program, it invoked a 68K emulator and you’re 68K code would run (albeit slow) on a PowerPC.

There’s a lot of cool technology involved in all this and Apple has always been very good at making this happen transparently and behind the scenes. The only thing you notice is that such programs don’t run very fast. Once every has Intel binaries (X86) then this won’t be necessary. Last time they did this, the 68K emulator was part of the OS for a long time, but it helped the transition a lot. You can expect the same thing with Rosetta… Reasonable performance for light-weight applications, but not good enough for heavy weight applications. I hear Photoshop runs OK under Rosetta but it’s noticablly slow for now.

You might consider joining the ADC (Apple Developer Connection) if you don’t already belong. That way you can read all the internal developer notes, get access to OS releases, and, depending on your membership level, get access to Apple Engineers and file bugs.

I suppose you know all this, but if you don’t, there it is.

Keep up the Podcasting, man!

Rick B.
rickbreen@comcast.net